Simulation method for flow field of multi-stage fracturing on horizontal well in tight oil reservoir

Patent metadata

Field	Value
Publication number	US-10976470-B2
Application number	US-202017021099-A
Country	US
Kind code	B2
Filing date	Sep 15, 2020
Priority date	Mar 26, 2020
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A simulation method for flow field of multi-stage fracturing on horizontal well in tight oil reservoir is provided. The tight oil reservoir comprises multiple horizontal wells with multi-stage fracturing, and for any horizontal well of the multiple horizontal wells, the method comprises: establishing a seepage mathematical model involving threshold pressure gradient according to reservoir physical property data and production data of the horizontal well, and determining formation pressure distribution of the horizontal well after multi-stage fracturing production according to the seepage mathematical model; determining formation pressure field distribution of the horizontal well after multi-stage fracturing production according to the formation pressure distribution and basing on principle of complex potential superposition; and establishing a criterion for identifying effective producing range of the horizontal well according to the formation pressure field distribution, and determining flow field range of the horizontal well according to the criterion.

First claim

What is claimed is:

1. A simulation method for a flow field of multi-stage fracturing on a horizontal well in a tight oil reservoir comprising multiple horizontal wells with multi-stage fracturing, and for any horizontal well of the multiple horizontal wells, the method comprises:
establishing a seepage mathematical model involving threshold pressure gradient according to reservoir physical property data and production data of the horizontal well, and determining formation pressure distribution of the horizontal well after multi-stage fracturing production according to the seepage mathematical model;
determining formation pressure field distribution of the horizontal well after multi-stage fracturing production according to the formation pressure distribution and based on principle of complex potential superposition; and
establishing a criterion for identifying effective producing range of the horizontal well according to the formation pressure field distribution, and determining the effective producing range of the horizontal well according to the criterion;
drilling the horizontal well based on the effective producing range;
wherein the method further comprises:
taking area of a region that meeting the criterion as production area A of the horizontal well, and determining geological reserves produced by the horizontal well according to the production area A;
N=A·h·ϕ·S oi ·ρ os /B o

wherein, N is geological reserves; A is production area; h is reservoir thickness; ϕ is porosity; S oi is initial formation oil saturation; ρ os is oil density at surface conditions; and B o is oil volume factor.

2. The method according to claim 1 , wherein before establishing the seepage mathematical model involving threshold pressure gradient, the method further comprises: obtaining the reservoir physical property data and the production data of the horizontal well;
the reservoir physical property data comprises formation thickness, porosity, permeability, oil saturation, threshold pressure gradient, formation fluid viscosity and initial formation pressure; and
the production data of the horizontal well comprises bottom hole flowing pressure and volume flow rate.

3. The method according to claim 1 , wherein the seepage mathematical model is

v
=

q

2
⁢
π
⁢
r
⁢
h

=

k
μ

⁢

(

d
⁢
p

dr

-
G

)

wherein, V is seepage velocity; q is volume flow rate; r is a distance from any point in formation to wellhead; h is formation thickness; k is permeability; μ is formation fluid viscosity; p is formation pressure; and G is threshold pressure gradient.

4. The method according to claim 3 , wherein the formation pressure distribution is

∫

p
⁡

(
r
)

p
e

⁢

d
⁢
p

=

q
⁢
μ

2
⁢
π
⁢
k
⁢
h

·

∫
r

r
e

⁢

1
r

⁢
d
⁢
r

+

G
·

(

r
e

-
r

)

wherein, p e is initial formation pressure; and r e is supply radius.

5. The method according to claim 4 , wherein the formation pressure field distribution is

∫

p
⁡

(
r
)

p
e

⁢

d
⁢
p

=

∑

i
=
1

n

⁢

[

q
i

⁢
μ

2
⁢
π
⁢

k
i

⁢
h

.

∫

r
i

r
ei

⁢

1

r

Assignees

• Univ Beijing Science & Technology

Inventors

• Zhu Weiyao
• Liu He
• Liu Yunfeng
• Shu Qinglin
• Song Zhiyong
• Yue Ming
• Wang Zenglin
• Kong Debin
• Li Aishan
• Li Bingbing
• Zou Guodong

Classifications

• E21B43/26 Primary

  by forming crevices or fractures · CPC title

• E21B2200/20

  Computer models or simulations, e.g. for reservoirs under production, drill bits · CPC title

• G06F30/20 Primary

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• E21B49/0875

  determining specific fluid parameters · CPC title

• G06F2113/08

  Fluids · CPC title